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AbstractGall wasps in the cynipid genus DiplolepisGeoffroy (Hymenoptera: Cynipidae) attack various species of native and introduced roses in Canada. Although gall forms are diverse, gall wasps are parasitised by highly concordant complexes of parasitoids and inquilines. Many species of gall wasps attack the same host plants and develop over the same periods in the season, suggesting that opportunistic parasitoids may be exploiting a range of hosts rather than specialising. We sampled larvae of EurytomaIlliger (Hymenoptera: Cynipidae) from galls of D. variabilis(Bassett) and D. rosaefolii(Cockerell), gall inducers that develop fairly synchronously late in the growing season on leaves of Rosa woodsiiLindl. (Rosaceae) in the Okanagan Valley of central British Columbia, Canada. Galls were sampled at five different sites along a gradient from the north end of the valley to the Canada–United States border, a distance of 100 km. We extracted DNA, then amplified and sequenced the cytochrome b segment for each Eurytomalarva. We identified two well-supported clades that were differentiated by neither sampling location nor host. Instead, at least two species of Eurytoma, E. imminutaBugbee and E. longavenaBugbee, exist at these localities, and both exploit at least two of the Diplolepishosts found at these sites.

AbstractWe evaluated the diversity and spatiotemporal emergence patterns of parasitoid wasp species in the genus EurytomaIlliger (Hymenoptera: Eurytomidae) associated with leaf galls induced by Diplolepis variabilisBassett (Hymenoptera: Cynipidae) throughout the Okanagan Valley, British Columbia, Canada. We collected D. variabilisgalls throughout the region, recorded adult Eurytomaemergence times, extracted mitochondria DNA from a subset of the emergents, and used cytochrome c oxidase 1 and cytochrome b amplificons to assign sampled individuals to species. We also assayed for the bacterial endosymbiont Wolbachiato evaluate the incidence of thelytoky in Eurytoma. Eurytomashowed an extended emergence period and a significant right skew in male emergence. We recorded six Eurytomaspecies, one of which appears to be previously undescribed. The greatest diversity of Eurytomaspecies occurs in the north of the sampled area. Five of the six species showed Wolbachiainfection in at least some individuals, and the most abundant and widespread species, Eurytoma imminutaBugbee, showed high Wolbachiainfection levels and an all-female population, which strongly indicates endosymbiont-induced thelytoky. Our results demonstrate that gall communities are locally variable, and we suggest that future studies be undertaken to quantify variation in community composition at more local scales than has been past practice.